1 . 某数学兴趣小组在数学实践课上开展了“菱形折叠”研究活动.
第一步:每人制作边长都为7的菱形纸片若干个,四个顶点为A、B、C、D(为保持一致,活动中,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bca5f6366db8d915043332f818b65d7c.png)
小组内制作图形各点名称命名规则相同);
第二步∶在边
上分别取点M、N(不含端点),将四边形
沿
翻折,使线段
的对应线段
经过顶点 D(点A、B分别与点 E、F对应).
操作判断![](https://staticzujuan.xkw.com/quesimg/Upload/formula/098a96d1e67d5e74d6122c8dfa63f183.png)
则
______.
迁移探究
(2)缜密小组按上述步骤折叠后如图2所示,已知![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c8861f0a5a206281022132864219f34d.png)
求
的长;
拓展延伸
(3)创新小组按上述步骤折叠后,要使
是以
为直角边的直角三角形,请你在图3 中帮他们画出满足条件的图形(草图即可),并求出对应的
的长.
第一步:每人制作边长都为7的菱形纸片若干个,四个顶点为A、B、C、D(为保持一致,活动中,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bca5f6366db8d915043332f818b65d7c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c915b4ce31fabfd4703c547291ad9277.png)
第二步∶在边
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2ba48366317ebea1c9dd5e4e67e03092.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/baa76cfd79a2ff6b28f370e54f4eb51d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
操作判断
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/098a96d1e67d5e74d6122c8dfa63f183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c915b4ce31fabfd4703c547291ad9277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf86f352a109022b6a849690bd0def8b.png)
迁移探究
(2)缜密小组按上述步骤折叠后如图2所示,已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c8861f0a5a206281022132864219f34d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c915b4ce31fabfd4703c547291ad9277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d50703c46b6153945d718b198f03b4b5.png)
拓展延伸
(3)创新小组按上述步骤折叠后,要使
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f44ca79d5e12bd02c393ba7f0b31c8c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b46c607b3deac746c0ef3389ad8f65c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7785afeeaf274892253d04b4f693b367.png)
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2 . 直观感知:
(
)如图
,在四边形
中,
是等边三角形,
,
,将
绕点
顺时针旋转
得
,点
与点
重合,点
的对应点是点
.补全图形,并直接写出
的度数;
类比探究:
(
)如图
,在四边形
中,
,
,
,
,
,求
的长.
拓展运用:
(
)如图
,在四边形
中,
,
,
,
,
,在
的变化过程中时,求
的最大值.
(
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ec5a330d2c4a8bec71d1f9fb053aa04.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42fa2dd034894609a52abc94f499b3cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e3a9ec45721f7b4d1c99917ac0d970f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be6a6301878fed2a01413020b27310a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9524e3810e06dc781285f1289e75d653.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ea98cd15fa4c868eb83ca260c6d9ae6.png)
类比探究:
(
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a22b02f6c8636152aeb62d191251e931.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed10df4140819d5451773a45de66201b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b10134e7a46e6f6f7cb9d5e2371727d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc11331a7b2d2619b40ee6d34c3bd620.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b277f34aa35e65d6562e87050197ecda.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
拓展运用:
(
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ca7d1107389675d32b56ec097464c14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ca7d1107389675d32b56ec097464c14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45acdbac251ca6b76a166c1242e71df9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3202b1d9f838c32ab5765ce647d96b6e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/846ee07de5ca5b23ae7d3fe240aca2c3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc11331a7b2d2619b40ee6d34c3bd620.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/430b77d8d2a99713b192dc729ddc2275.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
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3 . 综合与实践
李老师善于通过合适的主题整合教学内容,帮助同学们用整体的、联系的、发展的眼光看问题,形成科学的思维习惯.下面是李老师在“相似”主题下设计的问题,请你解答
【问题情境】
在中,
是
边上一点,
,
与
交于点
.
【初步探究】
(1)如图1,若,
于点
.
①求证.
②求的值.
【拓展延伸】
(2)如图2,是
延长线上一点,若
已知
,求
的长
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2024-01-06更新
|
198次组卷
|
3卷引用:2024年广西壮族自治区钦州市浦北县中考一模数学模拟试题
4 . 【定义呈现】有两个内角分别是它们对角的两倍的四边形叫做倍对角四边形,其中,这两个内角称为倍角.例如:如图1,在四边形
中,
,
,那么我们就叫这个四边形是倍对角四边形,其中
,
称为倍角.
【定义理解】如图1,四边形
是倍对角四边形,且
,
是倍角.求
的度数;
【拓展提升】如图2,四边形
是倍对角四边形,且
,
是倍角,延长
、
交于点A.在
下方作等边三角形
,延长
、
交于点G.若
,
,
,四边形
的周长记为
.
的代数式表示
;
(2)如图3,把题中的“
”条件舍去,其它条件不变.
①求证:
;
②探究
是否为定值.如果是定值,求这个定值,如果不是,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27bb421b8fb47716b09ea7367a8a6a42.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/525b212fc8e4a6e4e3238ef3037831e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3818a2c9919d358b4c3713396093822b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c543c3ddc3723fde6bbfca3ea3b921b.png)
【定义理解】如图1,四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3818a2c9919d358b4c3713396093822b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c543c3ddc3723fde6bbfca3ea3b921b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4453fb13033ef0e1547a41ed973940c7.png)
【拓展提升】如图2,四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1333acc72211e3ddb9a0f8c726ce8a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c5d3f1c7f7ffdf572978468d5a3adde.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d3e081637bcea5368cc72370bae283b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6830ebecddbd9759be626289c408e4f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/735056c174e8dd7906257a2a50a962a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef0402dd5ae3db10281f9f1e11738bcb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15d274d36400ca59460848b59307979c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1333acc72211e3ddb9a0f8c726ce8a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0a532e15e232cb4b99a8d4d07c89575.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
(2)如图3,把题中的“
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
①求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d707c196e6cab04a80151d542de9ee46.png)
②探究
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41bd21c7396562410aac59dfe6f01321.png)
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5 . (1)【问题发现】
如图1,在
中,
,
,点
为
的中点以
为一边作正方形
,点
恰好与点
重合,则线段
与
的数量关系为________.
(2)【拓展探究】
在(1)的条件下,如果正方形
绕点
旋转,请判断线段
与
的数量关系,并就图2的情形说明理由.
(3)【问题解决】
当
,且第(2)中的正方形
旋转到
,
,
三点共线时,请直接写出线段
的长.
如图1,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd967903ed5a6f640a5b801ec8be0070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dc9795efa99b6fb9fdf9778085dab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c06154cae3bf7a8ce5a1e97a7380875.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b32c05247f6998d7a70d31d13be4148c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
(2)【拓展探究】
在(1)的条件下,如果正方形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b32c05247f6998d7a70d31d13be4148c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
(3)【问题解决】
当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c3e9ef3e849788645552cfb0735d987.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b32c05247f6998d7a70d31d13be4148c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
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6 . 小东在刘老师的指导下开展“探究四点共圆的条件”活动,得出结论:对角互补的四边形四个顶点共圆.小东继续利用上述结论进行探究.
【提出问题】
如图1,在线段
同侧有两点B,D,连接
,如果
,那么A,B,C,D四点在同一个圆上.
探究展示:
【反思归纳】
(1)上述探究过程中的横线上填的内容是________;
【拓展延伸】
(2)如图3,在
中,
,将
绕点A逆时针旋转得
,连接
交
于点D,连接
.小东发现,在旋转过程中,
永远等于
,不会发生改变.
①根据
,利用四点共圆的思想,试证明
;
②当
为直角三角形,且
时,直接写出
的长.
【提出问题】
如图1,在线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/023f512b22fed30d4a9d3e408ef61350.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4fd85cff10e8f192cfe0b0a8b2f4996.png)
探究展示:
如图2,作经过点A,C,D的![]() ![]() 连接 ![]() ![]() 又∵ ![]() ∴___________, ∴点A,B,C,E四点在同一个圆上(对角互补的四边形四个顶点共圆), ∵点B,D在点A,C,E所确定的 ![]() ∴点A,B,C,D四点在同一个圆上. |
(1)上述探究过程中的横线上填的内容是________;
【拓展延伸】
(2)如图3,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd967903ed5a6f640a5b801ec8be0070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e64f5b5c0dd360f325604eaf7863bd7c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/246b32e19ae21b0cd1f826c47f517ca0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db54223bb3fc2fe2497213a4d1f94827.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7785afeeaf274892253d04b4f693b367.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1ae227a8df8dca0b13a17fcaf00cc96e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c9d16fab0f52c8af5abba0bf19a06ea0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79a97bb4dcfab4ec7539bc783d563c49.png)
①根据
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/700d23ec3e0d73c7a576b5f4b3b8a6b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b3048ae117572e24b27f176b28e89cf.png)
②当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/75a1219bc313db46b07bbd68600267a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bc9abe9e42cf396cf527b4ccbd2fefe7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
您最近一年使用:0次
名校
7 . 某“数学学习兴趣小组”成员在复习《图形的变化》时,对下面的图形背景产生了浓厚的兴趣,并尝试运用由“特殊到一般”的思想进行了探究:
〖问题背景〗如图1,正方形中,点E为
边上一点,连接
,过点
作
交
边于点
,将
沿直线
折叠后,点
落在点
处,当
,则
°.
〖特例探究〗如图2,连接,当点
恰好落在
上时,求证:
.
〖深入探究〗如图3,若把正方形改成矩形
,且
,其他条件不变,他们发现
与
之间也存在着一定的数量关系,请直接写出
与
之间的数量关系式.
〖拓展探究〗如图4,若把正方形改成菱形
,且
,
,其他条件不变,当
时,请直接写出
的长.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/17/095aebde-0520-4a36-933c-71b4605040b7.png?resizew=733)
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8 . (1)【问题探究】
如图1,
于点B,
于点C,
交
于点D,求证:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58187c069c0a20c9e111c591dc31d2a0.png)
(2)【知识迁移】
如图2,在矩形
中,E是
上的一点,作
交
于点F,
,若
,
,求
的值.
(3)【拓展应用】
如图3,菱形
的边长为5,
,E为
上的一点,过D作
E交
于点F,交
于点G,且
,求
的长.
如图1,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080db3af81b29ed10144a1c2e2a4fb8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/531d6f90f144551a35d494b1fe7d2b89.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b757706eee506a078fc25e3f33a70cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58187c069c0a20c9e111c591dc31d2a0.png)
(2)【知识迁移】
如图2,在矩形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8689d619c2508c9000531fc1b8f1f21c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c0d6068866683547b733dbe005031a6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc11331a7b2d2619b40ee6d34c3bd620.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/14a4c86103260c233b26ec7dc50ad1ed.png)
(3)【拓展应用】
如图3,菱形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/547f5f1377ef79e1369c19183066be62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/085cbdd37657b21dd1b686fc02d4f223.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab41892dcb2a6b84cb4056c9d00c7aab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
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9 . 综合与实践
数学活动课上,王老师带领学生利用手头的三角板进行了如下的探究:
三角板的直角顶点D放在
三角板的斜边
中点处转动,该三角板的两直角边与等腰直角三角板的两直角边
,
分别交于E、F两点,则线段
与
的数量关系是______;
(2)拓展探究:如图2,将一个足够大的
三角板的
角(
)顶点D放在
三角板的斜边
中点处转动,且
,该三角板的两边与
,
的延长线分别交于E、F两点,当
时,试确定
与
的数量关系,并说明理由;
(3)类比提升:如图3,将一个足够大的
三角板的直角顶点D放在
三角板的斜边
中点处转动,且
,该三角板的两直角边与
,
分别交于E、F两点,请直接写出线段
与
的数量关系(无需证明).
数学活动课上,王老师带领学生利用手头的三角板进行了如下的探究:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3527be15aa20f8c18c6ba772725e2b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/801c33a6f81b59ee686f4bd6c2dfc840.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
(2)拓展探究:如图2,将一个足够大的
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3527be15aa20f8c18c6ba772725e2b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be6a6301878fed2a01413020b27310a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f3bba5bd11e850c9b766c2ba6c426d1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3527be15aa20f8c18c6ba772725e2b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26fdd8e57562ba94e10e7f1d770826d0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7dea2ae9d515f9ab351ad72306b776ee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9abaeba15f3abdd877bc701af52c5cd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7faabc484ce3666706c1beffda4bcfe2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
(3)类比提升:如图3,将一个足够大的
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/801c33a6f81b59ee686f4bd6c2dfc840.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3527be15aa20f8c18c6ba772725e2b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26fdd8e57562ba94e10e7f1d770826d0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
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10 . 【问题提出】在等腰
中,
为
中点,以D为顶点作
,角的两边分别交
于点
,连接
,试探究点D到线段
的距离.
(1)先将问题特殊化,如图2,当点E和A重合时,直接写出D到线段
的距离(用含
的式子表示);
(2)再探究一般情形,如图1,证明(1)中的结论仍然成立;
【问题拓展】如图3,在等腰
中,
为
中点,以D为顶点作
,角的两边分别交直线
于点
,连接
.若
,直接写出
的值(用含
的式子表示).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26b14e714077541030828a4d960897ef.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4206739a0e94a7bd9f8dfc7576e90de8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7dec2ca6438c82b43f746057d8129885.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad056c25c0fdcbcc765eb5cbc6093f2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
(1)先将问题特殊化,如图2,当点E和A重合时,直接写出D到线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/234f1aebda05489b127ae977215e3fd4.png)
(2)再探究一般情形,如图1,证明(1)中的结论仍然成立;
【问题拓展】如图3,在等腰
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b90dc865781ebfe38b4a75d5184a8956.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4206739a0e94a7bd9f8dfc7576e90de8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7dec2ca6438c82b43f746057d8129885.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad056c25c0fdcbcc765eb5cbc6093f2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab00e0cff0876c4183a47f1272cf9928.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cabbf0a453ddfb49830fff20db61265.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6cc9750c313ee972124cb62c4a6fb7ea.png)
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